CN101388209B - Composition for acoustic damping - Google Patents

Composition for acoustic damping Download PDF

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CN101388209B
CN101388209B CN200810161134.6A CN200810161134A CN101388209B CN 101388209 B CN101388209 B CN 101388209B CN 200810161134 A CN200810161134 A CN 200810161134A CN 101388209 B CN101388209 B CN 101388209B
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complex
filler
sphenoid
damping
filamentary form
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CN101388209A (en
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W·罗
P·A·迈尔
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Waygate Technologies USA LP
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Everest Vit Inc
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    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08KUse of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K7/00Use of ingredients characterised by shape
    • C08K7/02Fibres or whiskers
    • C08K7/04Fibres or whiskers inorganic
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08KUse of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00Use of inorganic substances as compounding ingredients
    • C08K3/34Silicon-containing compounds
    • C08K3/36Silica

Abstract

The invention relates to a composition for acoustic damping. In one embodiment of the invention, a composition for a damping wedge in an ultrasonic probe having a wedge body is disclosed, the composition comprising: a viscoelastic material having a ratio of the imaginary part to the real part of the modulus of elasticity of at least about 5% and an acoustic impedance less than that of the wedge body; a filament-shaped filler in an effective amount to provide good dispersability in the viscoelastic material and to substantially match the acoustic impedance of the damping wedge to the wedge body; and a viscosity enhancer in an effective amount to increase the viscosity of the composition to maintain a homogenous distribution of the filament-shaped filler by preventing the filament-shaped filler from settling.

Description

Complex for acoustic damping
The cross reference of related application
The application requires in the U.S. Provisional Patent Application No.60/956 of application on August 17th, 2007,415 right of priority.
Technical field
The application is usually directed to the complex for acoustic damping, such as but be not limited to those complexs for the damping wedge of ultrasonic probe.
Background technology
The ultrasonic probe with phased array transducer injects tested target with the angle tilting by sound wave, so as for crack defect checkout target.When angle of inclination is greater than first critical angle, according to Snell law, compressional wave will disappear, and only the new shear wave being converted is propagated in tested target.The ultrasonic examination of going a long way greatly of the simplicity of pure wave pattern.For the sound wave of tested target shear wave preferably.The wedge with the angle that is greater than first critical angle is connected to transducer conventionally, to produce shear wave in tested target.Yet a part for the compressional wave producing by transducer is by from sphenoid-test target boundary reflection.If a plurality of being reflected in by array energy transducer of these compressional waves in wedge receives and be not eliminated before, the image that compressional wave echo generates at the ultrasonic shear waves echo from receiving, produce noise.
Transversal wave ultrasonic probe typically has the sphenoid being connected to respect to the angled lip-deep ultrasonic transducer on sphenoid surface, this sphenoid surface will contact tested target, and damping wedge is installed on the front side with respect to the sphenoid of transducer.Provide damping wedge for reducing as much as possible longitudinal wave reflection or the echo from the ultrasonic signal receiving.The ultrasonic signal that damping wedge must not only be decayed and be measured with dB per inch decay (dB/in.) form, and coupling is with the impedance of the sphenoid of Mrayl form measurement, it is abundant rigidity simultaneously, so that processed, and to keep its shape, it can be from getting rid of many kinds of substance for obtaining the consideration of damping wedge.
The decay of damping wedge and/or impedance matching are not usually best.Fig. 1 has described the problem relevant to prior art with Fig. 2.Fig. 1 shows situation when ought be insufficient by the decay of damping wedge 10.In this case, ultrasonic probe 50 has transducer 30, and this transducer produces vertical (L) ripple.A part for compressional wave (L) is converted into shear wave (S), when they incide the interface between sphenoid 20 and tested target 40.The shear wave being converted (S) is by tested target 40., from sphenoid-test target interface 35 reflected P-waves (L), enter the damping wedge 10 of prior art therebetween, and the echo returning through sphenoid-damping wedge interface 15 and sphenoid 20 subsequently still enough by force, to be received by transducer 30.As by as described in Fig. 2, when a little less than the damping wedge 10 of prior art and the impedance matching between sphenoid 20, compressional wave (L) reflects and echo doughtily from sphenoid-damping wedge interface 15 of the damping wedge 10 with prior art.
Each of these problems causes undesired compressional wave echo to be received by transducer, and produces noise signal.When ultrasonic frequency becomes lower, owing to coming the decay of self-damping to have the fact with the direct relation of frequency, noise increases.Operating frequency lower than 4MHz is supposed to for utilizing some target of ultrasonic inspection, still, and when utilizing known damping wedge material complex, from this inspection of noise of the compressional wave of not decaying.For example approximately the lower frequency of 1.5MHz to 2MHz provides larger penetration depth than the frequency that surpasses 2MHz, and this needs in some applications.But known damping wedge material complex is not enough to decay from the noise signal of compressional wave.
Ultrasonic probe deviser can utilize three kinds of mechanism to reduce noise-scattering, absorption and the ultrasonic geometric divergence from compressional wave.By adding filler to damping wedge material complex, produce scattering, for incoherent ground reflected P-wave.Absorption, by converting wave energy to heat, reduces wavelength, and absorbs relevant to the viscoelasticity of the material using.The v-groove that geometric divergence utilization forms in sphenoid-damping wedge interface.
Available damping wedge does not provide stability at lower frequencies such as the approximately sufficient damping of the compressional wave at 2MHz place.Fig. 3 and 4 has described spectral response and the decay that the damping wedge by prior art provides, the prior art damping wedge consists of the water-immersed .24 inch obtaining from Mereco Technologies Group company and the epoxy resin 303 of .48 inch piece, is known as " thin " and " thick " piece here.For example, chunk have between 4MHz to 2MHz operating frequency approximately-frequency response range of 40dB.Chunk and thin all demonstrate 4MHz place approximately-80dB/in., 2MHz place only-40dB/in., and 1MHz place is less times greater than the overall attenuation of-20dB/in..As found out in Fig. 4, it is linear that attenuation function is essentially, and has the approximately slope of-17.0 (dB/in.)/MHz.
Application dimension constraint also limits the size of damping wedge, and therefore limits the amount of the available damping material with the undesired sound wave of decaying.For example, the size of some application restric-tion damping wedges is to being less than half inch.Therefore, adding simply material to damping wedge is not for making damping selection more effectively.Damping wedge material complex must be also abundant rigidity, and they can utilize saw, grinding machine and other tool processes.
Therefore, exist for for obtaining the needs at the improved ultrasonic damping wedge of material complex of the relatively low effective damping wedge in ultrasonic frequency place.In addition need for designing the method for effective ultrasonic damping wedge for impedance matching and the decay of the undesired sound wave of optimization.Damping wedge material complex is rigidity fully, so that it can be processed to useful shape.
Summary of the invention
In one embodiment of the invention, disclose a kind of for thering is the complex of damping wedge of the ultrasonic probe of sphenoid, this complex comprises: viscoelastic material, the ratio of the imaginary part with at least about 5% elastic modulus to real part, and the acoustic impedance that is less than the acoustic impedance of described sphenoid; With the filler of the filamentary form of effective dose form, in order to the dispersibility that provides in described viscoelastic material and in order to substantially to make acoustic impedance and the described sphenoid of described damping wedge match; And with the viscosity-increasing agent of effective dose form, in order to increase the viscosity of described complex, so that by avoiding the filler precipitation of described filamentary form to keep the homogenous distribution of the filler of described filamentary form.
Accompanying drawing explanation
Fig. 1 is the right side elevation view of prior art ultrasonic probe;
Fig. 2 is another right side elevation view of prior art ultrasonic probe;
Fig. 3 shows as frequency the function of amplitude, for the curve map of the spectral response of the acoustical signal of the prior art damping wedge transmission by two different-thickness;
Fig. 4 shows as the function with the operating frequency of hertz form for the prior art damping wedge of Fig. 3, with the curve map of the acoustical signal decay of dB per inch form;
Fig. 5 is the right side elevation view of ultrasonic probe in one embodiment of the present of invention;
Fig. 6 shows in one embodiment of the present of invention (example 1), as frequency to the function of amplitude, and the curve map of the spectral response of the acoustical signal of the damping wedge transmission by two different-thickness;
Fig. 7 show as for the damping wedge of Fig. 6 with the function of the operating frequency of hertz form, with the curve map of the acoustical signal decay of dB per inch form;
Fig. 8 shows in one embodiment of the present of invention (example 2), as frequency to the function of amplitude, and the curve map of the spectral response of the acoustical signal of the damping wedge transmission by two different-thickness;
Fig. 9 show as for the damping wedge of Fig. 8 with the function of the operating frequency of hertz form, with the curve map of the acoustical signal decay of dB per inch form;
Figure 10 shows in one embodiment of the present of invention (example 3), as frequency to the function of amplitude, and the curve map of the spectral response of the acoustical signal of the damping wedge transmission by two different-thickness; And
Figure 11 shows as the function with the operating frequency of hertz form for the damping wedge of Figure 10, with the curve map of the acoustical signal decay of dB per inch form;
Figure 12 shows in one embodiment of the present of invention (example 4), as frequency to the function of amplitude, and the curve map of the spectral response of the acoustical signal of the damping wedge transmission by two different-thickness; And
Figure 13 show as for the damping wedge of Figure 12 with the function of the operating frequency of hertz form, with the curve map of the acoustical signal decay of dB per inch form.
Embodiment
Referring now to accompanying drawing; wherein similarly reference number is used for representing identical or relevant element; Fig. 5 has described the ultrasonic angle beam type probes 50 that has, and this probe has with the surperficial certain angle with respect to tested target 40 and is assemblied in sphenoid or the ultrasonic transducer 30 of protection on piece 20.To be greater than the angle assembling transducer 30 according to the first critical angle of Snell law, to guarantee that the compressional wave (L) producing will be converted into shear wave (S) at 35 places, sphenoid-test target interface.At interface, 15 places are connected to sphenoid 20 to damping wedge 60.As described in this and the structure of the ultrasonic probe 50 for ultrasonic wedge illustrated in the accompanying drawings, sphenoid 20 and damping wedge 60 and arrange it is only descriptive.
As shown at the accompanying drawing of Fig. 5, the shear wave being represented by arrow S from compressional wave (L) conversion of incident, and propagates through tested target 40 at 35 places, sphenoid-test target interface.The compressional wave being represented by arrow L is reflected off the surface of tested target 40, through sphenoid-damping wedge interface 15, and starts decay in damping wedge 60.The attenuation characteristic of damping wedge 60 is such: before again reaching sphenoid-damping wedge interface 15 from damping wedge 60 sides, compressional wave L is by damping or decay completely.Because compressional wave L is by complete attenuation, in the ultrasonic echo being received by transducer 30, there is not noise component, and therefore can obtain from the noisy image of not having of undesired ultrasonic longitudinal wave.
Damping wedge 60 produces the useful effect of eliminating compressional wave L reflection, because damping wedge 60 is to mate with the acoustic impedance of sphenoid 20, utilizes mechanism of absorption that high acoustical signal decay is also provided, so that wave energy dissipates into heat simultaneously.In an embodiment of damping wedge 60, such as but be not limited to the viscoelastic material of epoxy resin, the ratio of its imaginary part with at least about 5% elastic modulus to real part, and the acoustic impedance with the impedance that is less than sphenoid 20 exists with the amount of 100 weight portions.The attenuation coefficient (for example approximately-65 (dB/in.)/MHz) that damping wedge 60 demonstrated significantly and be greater than-17.0 (dB/in.)/MHz is to about-85 (dB/in.)/MHz) between scope in).Discussion below will be explained elastic modulus component and the relation of further selecting.
As will be appreciated, for viscoelastic material, elastic modulus can be expressed as plural number:
E *=E′+iE″(1)
Wherein, E ' is storage modulus, and E " be loss modulus.
For pure resilient material, the imaginary part of equation (1) is zero, and does not therefore have loss or decay.The loss modulus of viscoelastic material is never zero.So E " larger, absorb or decay larger.Typically, more tacky or softer material provides larger viscoelasticity, and therefore provides higher decay.
It is a multidimensional problem that ripple in viscoelastic material is propagated, but can be regarded as one-dimensional problem in order to simplify it:
d 2 u dx 2 = 1 c * ( iω ) 2 d 2 u dt 2 - - - ( 2 )
Displacement components u can be expressed as along the function of the time of x-axle dimension:
u ( x , t ) = Ae i ( ωt - k * x ) = Ae i ( ωt - ( k ′ + ik ′ ′ ) x ) ) = Ae k ′ ′ x e i ( k ′ x - ωt ) = Ae - α ( ω ) x e i ( ω c ( ω ) x - ωt ) - - - ( 3 )
K wherein *be the compound wave number that is derived from the viscoelastic property of damping material, and α (ω) is attenuation coefficient, it is compound wave number k *imaginary part:
Figure G2008101611346D00053
Figure G2008101611346D00054
Therefore by following formula, provide the decay about dB:
Attenuation(dB)=201og 10(e -α(ω)x)=-α(ω)x201og 10(e)=-8.69α(ω)x(6)
And accordingly, decay can be expressed as the function for the intrinsic compound substance characteristic of viscoelasticity.Attenuation coefficient α (ω) is the attenuation coefficient that can be expressed as following formula:
α ( ω ) = Im [ - ω c * ( ω ) ] - - - ( 7 )
Wherein compound velocity of longitudinal wave is:
c 1 * = E * ( 1 - v * ) ρ ( 1 + υ * ) ( 1 - 2 υ * ) - - - ( 8 )
Wherein v is Poisson ratio, and provides compound shear wave velocity by following formula:
c 2 * = G * ρ - - - ( 9 )
Therefore, by speed and the decay of material, can express the composite attribute of viscoelastic material.Speed is expressed as:
c * ( ω ) = 1 1 c ( ω ) - i α ( ω ) ω - - - ( 10 )
Young modulus is expressed as:
E * = [ 3 - 4 ( c 2 * c 1 * ) 2 1 - ( c 2 * c 1 * ) 2 ] G * = [ 3 - 4 ( c 2 * c 1 * ) 2 1 - ( c 2 * c 1 * ) 2 ] · c 2 * 2 · ρ = [ 3 - 4 ( c 2 ω - ic 1 c 2 α 1 c 1 ω - ic 1 c 2 α 2 ) 2 1 - ( c 2 ω - ic 1 c 2 α 1 c 1 ω - ic 1 c 2 α 2 ) 2 ] · ( c 2 ω ω - ic 2 α 2 ) 2 · ρ - - - ( 11 )
And provide modulus of shearing by following formula:
G * = μ * = c 2 * 2 · ρ = [ 1 c 2 ( ω ) - i α 2 ( ω ) ω ] - 2 · ρ = ( c 2 ω ω - ic 2 α 2 ) 2 · ρ - - - ( 12 )
C wherein 1velocity of longitudinal wave, and c 2it is shear wave velocity.
Below, Rayleigh (Rayleigh) damper model is considered to produce damping loss factor, and this damping loss factor can be for assessment of material viscoelasticity and decay.Governing equation for dynamic system is:
[ M ] { D · · } + [ C ] { D · } + [ K ] { D } = { R ext } - - - ( 13 )
And Rayleigh damping is expressed as:
[C]=α[M]+β[K](14)
Wherein the mark of critical damping is:
ξ = α R 2 ω + β R ω 2 - - - ( 15 )
And α wherein rmass ratio factor, the frequency that its damping is lower, and caused by the model sport by viscous fluid, and therefore relate to absolute model velocity, while β rrigidity ratio damping factor, the frequency that its damping is higher, and relate to tack of materials characteristic, and proportional with rate of strain.This causes the expression formula of damping loss factor to be:
η = E ′ ′ E ′ = 2 ξ = 2 ( α R 2 ω + β R ω 2 ) ≈ β R ω - - - ( 16 )
Wherein can find out, for given frequencies omega, the imaginary part of elastic modulus with respect to the ratio direct proportion of the real part of elastic modulus in rigidity ratio damping factor.
According to embodiments of the invention, the imaginary part with at least about 5% elastic modulus is to the ratio of real part and be less than the viscoelastic material and the filler combination with filamentary form of the impedance of sphenoid 20, has greatly improved acoustic damping performance.The non-limitative example of this viscoelastic material comprises that epoxy resin is (for example, from MerecoTechnologies Group, the obtainable epoxy resin of company, or from the obtainable STYCAST1265A/B epoxy resin of Emerson & Cuming).The non-limitative example of the filler of filamentary form comprises inorganic crystal whisker and fiber ceramics.The non-limitative example of inorganic crystal whisker and fiber ceramics comprises glass fibre (for example, from the obtainable 731EC Milled of OwensCorning Co.) and alumina fibre (for example, from the obtainable NEXTEL610 of 3M Co.).The filler of filamentary form is provided with effective dose form, so that the dispersibility providing in viscoelastic material, thus and the acoustic impedance that makes the acoustic impedance of potpourri substantially mate sphenoid 20.It is acceptable causing the impedance matching of the total reflection of being less than of compressional wave about 6%.With as for increasing the needed amount of the viscosity of potpourri, add viscosity-increasing agent, and therefore by avoiding filler precipitation to keep the homogenous distribution of the filler of filamentary form.Viscosity-increasing agent can be the inorganic filler with the particle size that is less than 1 micron.The non-limitative example of viscosity-increasing agent comprises amorphous silicon (for example, from the untreated fumed silica of the obtainable CAB-O-SIL of Cabot Corp).
Table 1 has below been described the complex having for the characteristic of the damping wedge 60 of several embodiments of the present invention:
Table 1-damping wedge material complex
Figure G2008101611346D00071
Figure G2008101611346D00081
In table 1, modular ratio is listed as the imaginary part of the elastic modulus that relates to viscoelastic material with respect to the ratio of real part, and the weight portion of the every part that comes across formula is shown in weight list.Set up formula 1-12 and show extraordinary damping characteristic.In the whole circumstances, the optimised quantity of the filler of the filamentary form adding will depend in part on the acoustic impedance of the sphenoid 20 using together with damping wedge 60, this is to improve the acoustic impedance of damping wedge 60 material complexs because add filler, to as far as possible closely mate the acoustic impedance of sphenoid 20.
Be appreciated that different sphenoids 20 materials have different acoustic impedances.Yet, can expect, sphenoid 20 materials are by the acoustic impedance having between about 1.5-3.5Mrayl mostly.Therefore, the viscoelastic material that the ratio with the component of elastic modulus is at least about 5% will also have in same range as and lower acoustic impedance, therefore the acoustic impedance of damping wedge 60 material complexs can be enhanced, so that the acoustic impedance of mating sphenoid 20 by adding the filler of filamentary form.
In example below, further describe exemplary damping wedge 60 material complexs.
Example 1
By the fiber glass packing of the epoxy resin No.2 with 100 weight portions and 33 weight portions, and the fumed silica viscosity-increasing agent of 3 weight portions combines to obtain damping wedge 60 material complexs, to improve acoustic impedance to 2.5Mrayl.The acoustic impedance of the expectation of 2.5Mrayl matches with the polystyrene sphenoid 20 with the acoustic impedance of approximately uniform 2.5Mrayl.Shown in Fig. 6 and 7, the frequency response and the decay that by damping wedge 60 material complexs, provide are extraordinary.Fig. 6 has described, and is compared to the wedge of thin (.24 inch), the frequency response of the acoustical signal of the wedge transmission by thick (.48 inch).In Fig. 7, dotted line is that the best-fit of the actual attenuation value that represents by solid line is linear approximate.With the damping wedge 60 of the ratio manufacture of weight portion 100/33/3 only demonstrate sphenoid-damping wedge interface 15 reflections of about 2%, approximately the attenuation coefficient of-85.9 (dB/in.)/MHz and 1MHz place approximately-decay of 106dB/in., thereby basic elimination is from the noise of compressional wave.Damping wedge 60 material complexs are enough firm, this make its can be processed to form damping wedge 60 shapes of expectation.
Example 2
By ratio associative ring epoxy resins No.2, fiber glass packing and fumed silica viscosity-increasing agent with 100/20/3 to obtain damping wedge 60 material complexs.Shown in Fig. 8 and 9, the frequency response and the decay that by damping wedge 60 material complexs, are provided are extraordinary.Fig. 8 has described the wedge that is compared to thin (.24 inch), the frequency response of the acoustical signal of the wedge transmission by thick (.48 inch).In Fig. 9, dotted line is that the best-fit of the actual attenuation value that represents by solid line is linear approximate.The attenuation coefficient of linear-apporximation is-72.2 (dB/in.)/MHz, and the decay at 2MHz place is simultaneously approximate is-175dB/in..Be matched with the impedance of the polystyrene sphenoid 20 of the acoustic impedance with 2.5Mrayl, it causes in 15 places about 6%, sphenoid-damping wedge interface or less reflection.Damping wedge 60 material complexs are enough firm, so that it can be processed to form damping wedge 60 shapes of expectation.
Example 3
By ratio associative ring epoxy resins No.2, fiber glass packing and fumed silica viscosity-increasing agent with 100/30/3 to obtain damping wedge 60 material complexs.Shown in Figure 10 and 11, the frequency response and the decay that by damping wedge 60 material complexs, provide are extraordinary.Figure 10 has described, and is compared to the wedge of thin (.24 inch), the frequency response of the acoustical signal of the wedge transmission by thick (.48 inch).In Figure 11, dotted line is that the best-fit of the actual attenuation value that represents by solid line is linear approximate.The attenuation coefficient of linear-apporximation is-82.1 (dB/in.)/MHz, and the decay at 2MHz place is simultaneously approximate is-175dB/in..Be matched with the impedance of the polystyrene sphenoid 20 of the acoustic impedance with 2.5Mrayl, the reflection that it causes 15 places, sphenoid-damping wedge interface to be less than 3%.Damping wedge 60 material complexs are enough firm, so that it can be processed to form damping wedge 60 shapes of expectation.
Example 4
By the ratio associative ring epoxy resins No.2 with 100/15/4, alumina fibre filler (ground connection a little) and fumed silica viscosity-increasing agent to obtain damping wedge 60 material complexs.Shown in Figure 12 and 13, the frequency response and the decay that by damping wedge 60 material complexs, provide are extraordinary.Figure 12 has described, and is compared to the wedge of thin (.24 inch), the frequency response of the acoustical signal of the wedge transmission by thick (.48 inch).In Figure 13, dotted line is that the best-fit of the actual attenuation value that represents by solid line is linear approximate.The attenuation coefficient of linear-apporximation is-64.9 (dB/in.)/MHz, and the decay at 2MHz place is simultaneously approximate is-130dB/in..Be matched with the impedance of the polystyrene sphenoid 20 of the acoustic impedance with 2.5Mrayl, the reflection that it causes 15 places, sphenoid-damping wedge interface to be less than 4%.Damping wedge 60 material complexs are enough firm, so that it can be processed to form damping wedge 60 shapes of expectation.
Table 2 below demonstrates the material behavior of measurement, comprises the attenuation coefficient of several damping wedge 60 material complexs:
The sound characteristics that table 2-damping wedge material is measured
Material c 1(km/Sec) α 1(dB/in.)/MHz α 1/ω(Sec/km) c 2(km/Sec) α 2/ω(Sec/km) ρ(gm/cm 3)
Epoxy resin No.1 (Mereco303) 2.17 -17.0 0.013 99 0.0373 1.05
Epoxy resin No2 (STYCAST1265) 1.86 -48.6 0.0334 0.85 0.0958 1.09
Example 2 epoxy resin No.2/ fiber glass packing/fumed silica viscosity-increasing agents (100/20/3) 2.00 -72.2 0.0521 .91 0.1495 1.23
Example 3 epoxy resin No.2/ fiber glass packing/fumed silica viscosity-increasing agents (100/30/3) 2.10 -82.1 0.0592 .96 0.170 1.29
Example 1 epoxy resin No.2/ fiber glass packing/fumed silica viscosity-increasing agent (100/33/3) 2.20 -85.9 0.0620 1.01 0.178 1.31
Example 4 epoxy resin No.2/ alumina fibre filler/fumed silica viscosity-increasing agents (100/15/4) 1.91 -64.9 0.0468 0.88 0.134 1.23
Table 3 below illustrates the damping loss factor ratio for the calculating of identical damping wedge 60 material complexs:
Table 3-damping wedge material characteristic (compound)
Figure G2008101611346D00111
Can find out, for each material subsequently, the attenuation coefficient α in table 2 1, as the damping loss factor in table 3, increase.
According to the damping wedge 60 material complexs of embodiments of the invention, allow the low frequency ultrasound inspection of the relatively little composition in the finite space.Due to high attenuation coefficient and the impedance of mating with sphenoid 20, damping wedge 60 material complexs allow there is no the ultrasonic probe of noise, to substantially eliminate the undesired longitudinal wave reflection from sphenoid-damping wedge interface 15.Damping wedge 60 material complexs allow undersized damping wedge 60 to be used to eliminate the noise that compressional wave of conversion does not cause by being produced by ultrasonic transducer 30.By reducing wedge size, can be for example more close pipe welding of wedge with shorter front end is positioned, thereby allows to be required the potentiometry of the crackle that the probe in detecting of larger wedge arrives, with noise decrease to acceptable level.
This printed instructions utilizes example to disclose the present invention, comprises optimal mode, and also allows any those skilled in the art to obtain and utilize the present invention.By claim, limit the Patent right scope that obtains of the present invention, and can comprise other example appearing in face of those skilled in the art.This other example is defined as in the scope of claim, if they have the structural detail not identical with the word language of claim, if or they comprise having and the word language of the claim equivalent construction element without essential difference.
Component list:
10 prior art damping wedges
15 sphenoids-damping wedge interface
20 sphenoids
30 transducers
35 sphenoids-test target interface
40 tests
50 probes
60 damping wedges

Claims (19)

1. for having the complex of damping wedge for the ultrasonic probe of sphenoid, described complex comprises:
Viscoelastic material, the ratio of its imaginary part with at least 5% elastic modulus to real part, and the acoustic impedance that is less than the acoustic impedance of described sphenoid;
The filler of filamentary form, in order to provide dispersibility and substantially to make the acoustic impedance of described damping wedge and described sphenoid match in described viscoelastic material; And
Viscosity-increasing agent, thus in order to the viscosity that increases described complex so that by avoiding the filler precipitation of described filamentary form to keep the homogenous distribution of the filler of described filamentary form,
Wherein, the filler of described viscoelastic material, described filamentary form and the percentage by weight of described viscosity-increasing agent in described complex are respectively 100/141 to 100/108,5/108 to 40/141 and 1/141 to 4/141.
2. the complex of claim 1, wherein said complex is abundant rigidity, thereby allows to be processed to the shape of expectation.
3. the complex of claim 1, wherein said complex has the attenuation coefficient that is greater than-17.0 (dB/in.)/MHz.
4. the complex of claim 1, the filler of wherein said filamentary form is inorganic crystal whisker.
5. the complex of claim 1, the filler of wherein said filamentary form is fiber ceramics.
6. the complex of claim 1, the filler of wherein said filamentary form is glass fibre.
7. the complex of claim 1, the filler of wherein said filamentary form is alumina fibre.
8. the complex of claim 1, wherein said viscoelastic material is epoxy resin.
9. the complex of claim 1, wherein said viscoelastic material has the acoustic impedance between 1.5 to 3.5Mrayl.
10. the complex of claim 1, wherein said viscosity-increasing agent is inorganic filler.
The complex of 11. claims 10, wherein said inorganic filler is amorphous silicon.
The complex of 12. claims 11, wherein said amorphous silicon is untreated fumed silica.
13. 1 kinds for the crackle of checkout target or the ultrasonic probe of defect, and described ultrasonic probe comprises:
At least one is for injecting ripple at the top of one's voice the transducer of described test target;
The sphenoid that is attached to described at least one transducer, it is configured to described ripple to be at the top of one's voice sent to described test target from described at least one transducer;
Be attached to the damping wedge of described sphenoid, the ripple at the top of one's voice arbitrarily that it is configured to receive and decays from the described ripple at the top of one's voice of the boundary reflection of described sphenoid and described test target;
Wherein said damping wedge is made by following complex, and described complex comprises:
Viscoelastic material, the ratio of its imaginary part with at least 5% elastic modulus to real part, and the acoustic impedance that is less than the acoustic impedance of described sphenoid;
The filler of filamentary form, in order to provide dispersibility and substantially to make the acoustic impedance of described damping wedge and described sphenoid match in described viscoelastic material; And
Viscosity-increasing agent, thus in order to the viscosity that increases described complex so that by avoiding the filler precipitation of described filamentary form to keep the homogenous distribution of the filler of described filamentary form,
Wherein, the filler of described viscoelastic material, described filamentary form and the percentage by weight of described viscosity-increasing agent in described complex are respectively 100/141 to 100/108,5/108 to 40/141 and 1/141 to 4/141.
The ultrasonic probe of 14. claims 13, wherein said complex is abundant rigidity, thereby allows to be processed to the shape of expectation.
The ultrasonic probe of 15. claims 13, wherein said complex, wherein said complex has the attenuation coefficient that is greater than-17.0 (dB/in.)/MHz.
The ultrasonic probe of 16. claims 13, the filler of wherein said filamentary form is inorganic crystal whisker.
The ultrasonic probe of 17. claims 13, the filler of wherein said filamentary form is fiber ceramics.
The ultrasonic probe of 18. claims 13, the filler of wherein said filamentary form is glass fibre.
The ultrasonic probe of 19. claims 13, the filler of wherein said filamentary form is alumina fibre.
CN200810161134.6A 2007-08-17 2008-08-15 Composition for acoustic damping Expired - Fee Related CN101388209B (en)

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